This Phase I proptocol for the evaluation of safety and immunogenicity of a recombinant, serum-free, influenza hemagglutinin (rHA0) vaccine is designed to generate immunity to the new H5N1 strain of avian influenza recently reported in 18 confirmed cases in humans in Hong Kong, including 6 fatalities as of January 14, 1998. The H5N1 strain is thought to have been transmitted from the avian species directly to humans, and could become a source of epidemic influenza if efficiently transmitted between humans. From a public health perspective, the development of a H5N1 vaccine which can be used to protect laboratory and public health personnel currently at occupational risk is of the highest priority. The objective of this protocol is to immunize laboratory and public health personnel currently manipulating the H5N1 influenza virus or working with potentially infected secretions, with an experimental, purified influenza H5 hemagglutinin (rHA0) vaccine produced in the baculovirus expression system, administered as a two-dose vaccine. A common protocol will be used at multiple sites to administer the vaccine and safety and immunogenicity data will be collected in a standardized manner.